A persona's notification policy and its requests

Mastodon 4.3's policy was a stub that accepted everything. It is now kept per persona: notifications from accounts it
does not follow, accounts that do not follow it (or only for three days), accounts newer than 30 days, private mentions
it did not ask for and silenced accounts are accepted, filtered or dropped. Filtered ones stay out of every list and
count unless asked for, gathered in a request per account; letting a request in lets that account in for good,
dismissing it deletes them. Everything is accepted until the persona chooses.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01LsXgEaXee4GCU1hwYgPJXw

CLAUDE.md

@@ -272,6 +272,11 @@ group www-data and reaches the private mongod; `sudo -u www-data` works too.
 6. Advertise `4.2.0 (compatible; PrivaPub)` until streaming and Web Push exist too; `api_versions.mastodon = 7` stays,
    because clients show quotes from it, so everything a 4.3+ client calls because of it must answer: grouped
    notifications (`/api/v2/notifications`, its unread count, groups, accounts and dismiss) and the notification policy.
+   The policy is real (`Domain/Social/NotificationPolicies.cs`, applied in `Notifications.Add`): accepted by default,
+   it filters (into a `NotificationRequest` per account, out of every list and count unless `include_filtered`) or drops
+   what strangers, accounts that do not follow the persona (or only for three days), accounts newer than 30 days,
+   unasked private mentions and silenced accounts send; accepting a request lets that account in for good
+   (`NotificationPermission`).
 7. **What a Mastodon `Status` cannot say goes in `Status.privapub`** (`PrivaPubStatus`): object type, title, excerpt,
    cover, the author's source, link, video, audio and event details, a remote post's own place (Pixelfed's `location`,
    never federated again), and up/down votes. Every media URL in it goes